Rudder for ships and boats



Feb. 21,5196] m RsspN ETAL 2,972,323

RUDDER FOR SHIPS AND BOATS Filed April 28. 1959 2 Shets-Sheet 1 //v VEN O. EINARSSON S. H. OLAFSSON QT'TOENED 21, 1961 o. EINARSSON ETAL 2,972,323

RUDDER FOR SHIPS AND BOATS 2 Sheets-Sheet 2 filed April 28. 1959 g pTToelvb United States Patent-O RUDDER FOR SHIPS AND BOATS Olafur Einarsson, 164 Sogaveg, and Sigurdur Hilmar Olafsson, 12 Baldurshaga 01f, both of Sudurlandsbraut, Reykjavik, Iceland Filed Apr. 28, 1959, Ser. No. 822,761

Claims. (Cl. 114-162) This invention relates to rudders for propeller driven ships or boats which are hereinafter referred to as vessels.

The revolution of the propeller or propellers of a vessel produces turbulence in the water near the rudder or rudders of the vessel, and the turbulence reduces the effectiveness of the rudder or rudders.

The object of the present invention is to avoid this reduction in effectiveness.

According to the present invention a rudder for a propeller driven vessel is provided with a pair of laminar members mounted one on each side of the rudder by supporting means, so that the leading edges of the rudder and laminar members are substantially in a common plane, said members being arranged so as to allow water to flow freely between each side of the rudder and the adjacent laminar member, to reduce turbulence in the water adjacent the rudder.

The inclusion of the laminar member in the construction of the rudder also serves to increase the effective area of the rudder, without increasing the dimensions of the rudder in a fore and aft direction.

Preferably the supporting means are streamlined struts.

The laminar members may be located so as to direct water flow onto the lee-side of a rudder upon deflection of the latter from the longitudinal axis of the vessel.

In order that the invention may be better understood and carried into practice, reference will now be made to the accompanying drawings, wherein:

Figures 1 and 2 are diagrammatic plan views of a conventional ships rudder and the adjacent portion of a ship having twin propellers;

Figures 3 and 4 are views similar to Figures 1 and 2, but showing the rudder of the present invention;

Figure 5 is a side elevation of a boat;

Figure 6 is an elevation on an enlarged scale of the rudder of the boat shown in Figure 5; j t

Figure 7 is a view on the line VII-VII of Figure' 6; and

Figure 8 is a rear elevation of the rudder shown in Figures 6 and 7.

Referring first to Figures 5 to 8, the rudder 10 shown therein is pivoted about a post 11. A pair of laminar members 12 each comprising a generally rectangular plate curved to the same general profile as the adjacent rudder face is spaced upon opposite sides of the rudder.

Each laminar member is approximately half as long as the rudder, i.e., measured in a fore and aft direction, and two-thirds of the height of the rudder; and the members are so arranged that their leading edges 14 lie in a plane common to that containing the leading edge 15 of the rudder.

The two members ll converge towardsthe rudder at their trailing ends 13. For example, in a rudder where the laminar members are approximately 80 cm. long,

Patented Feb. 21, 1961 7 Six of the struts 17 are arranged in two groups of three,

the struts in each group being disposed vertically one above another and extending horizontally between the rudder and the associated laminar member. The remaining two struts 16 are located one above and one below and centrally in relation to the groups of struts 17. The upper of the two struts 16 is inclined so as to extend downwardly to the laminar member 12 and the lower of the two struts 16 is inclined so as to extend upwardly to the laminar member.

Referring now to Figures 3 and 4 which show diagrammatically the flow of water past a rudder constructed according to the present invention, it will be noted that the propellers 18 cause little, if any, turbulence in the water, which is channeled to flow smoothly past the rudder. The lack of turbulence is particularly noticeable between the rudder and the laminar members, and the effect is more pronounced at high rudder angles, such as that illustrated in Figure 4.

The reduction in turbulence around the rudder is particularly illustrated by comparing Figure 2, which shows a conventional rudder not made or equipped in accordance with the invention, with Figure 4.

- What we claim then is: i

l. A rudder. for a propeller driven vessel, provided with a pair of laminar members mounted one on each side of the rudder so as to be movable therewith, the leading edges of the rudder and laminar members being substantially in a common plane, and the laminar members being spaced from the adjacent side surfaces of the rudder and being curved so as to converge at their trailing dges.

2. A rudder, for a propeller driven vessel, the rudder having a streamlined sectional shape and being provided with a pair of laminar members mounted one on each side of the rudder so as to be movable therewith, the leading edges of the rudder and laminar members being substantially in a common plane, the laminar members being spaced from the adjacent side surfaces of the rudder and each laminar member being curved to conform with the profile of the adjacent side surface of the rudder and such that the laminar members converge at their trailing edges.

3. A rudder, for a propeller driven vessel, the rudder having a streamlined sectional shape and being provided with a pair of laminar members, supporting means for mounting the laminar members one on each side of, and spaced from, the rudder so as to be movable therewith, the leading edges of the rudder and laminar members being substantially in a common plane, each laminar member being curved to conform with the profile of the adjacent side surface of the rudder and such that the having a streamlined sectional shape, a pair of laminar members mounted one on each side of the rudder so as to be movable therewith, each laminar member being a substantially rectangular sheet spaced from the adjacent 7 side surface of the rudder and curved to conform with the profile thereof such that the laminar members converge at their trailing edges, the rectangular members 3 being mounted with their leading edges substantially in a common plane with the leading edge of the rudder, and each laminar member extending rearwardly for half the length of the rudder from its leading edge.

5. A rudder as claimed in claim 4, in which the vertical dimension of each laminar member is half the vertical dimension of the rudder and the laminar member is symmetrically positioned in relation to the upper and lower extremities of the rudder.

4 References Cited in the file of this patent UNITED STATES PATENTS 99,639 Coleman 'Feb. 8, 1870 FOREIGN PATENTS 411,564 Germany Mar. 28, 1925 911,469 Germany May 13, 1954 

